var liArr = document.querySelectorAll("#about_us_content li");
var sliderDiv = document.querySelector(".slider");
var timer;
for(var i = 0; i < liArr.length; i++) {
	liArr[i].ind = i;
	liArr[i].onmouseover = function() {
		var t = 0;
		var start = sliderDiv.offsetLeft;
		var end = this.ind * this.offsetWidth;
		var change = end - start;
		var d = 50;
		clearInterval(timer);
		timer = setInterval(function() {
			t++;
			if(t > d) {
				clearInterval(timer);
			}
			sliderDiv.style.left = Tween.Back.easeOut(t, start, change, d) + "px";
			//						    t 动画 			当前时间  
			//							start  动画 		开始位置  
			//							change 动画 		变化量 
			//							d 动画 			总时间 
		}, 20)
	}
}

var liArr = document.querySelectorAll("#about_us_content ul li");
var divArr = document.getElementsByClassName("selected");
console.log(liArr);
console.log(divArr);
for(var i = 0; i < liArr.length; i++) {
	liArr[i].ind = i;
	liArr[i].onclick = function() {
		for(var i = 0; i < divArr.length; i++) {
			divArr[i].style.display = "none";
		}
		divArr[this.ind].style.display = "block";
	}
}